error log not logging

my error log in my DEFAULT virtual host is not logging at all in the error.log file even if i specify to use the main server error.log file and this is doing this in version 2.2.6 and 3.0.1 .....the access.log works fine.....weird!!!!

Please check the log level, maybe there is nothing to log.
If you select to use the main server error.log, it will not log to the vhost error log.

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I tried error level and debug level and tried to go to an unexisting web page on my server to make a 404 error and it logged it in the access.log but not in the error.log ether when i choose the vhost error log or the main server error log......if i activate the debug level do you think it will tell me what's wrong and if yes it will be in wich log file ?